Measuring deformation threshold of produce

Abstract

A system comprising a testing device comprising: a probe configured to be advanced to engage a produce item positioned in relation to the testing device, and at least one sensor configured to measure a resisting force by the produce item to the advancing; at least one hardware processor; and a non-transitory computer-readable storage medium having stored thereon program instructions, the program instructions executable by the at least one hardware processor to: operate the testing device to continuously advance the probe to engage a surface of the produce item while measuring the resisting force, discontinue the advancing when the resisting force ceases to increase as a result of the advancing, and determine a highest resisting force measured during the advancing, wherein the highest resisting force is indicative of a firmness value of the produce item.

What is claimed is: 
     
         1 . A system comprising:
 a testing device comprising:
 a probe configured to be advanced to engage a produce item positioned in relation to said testing device; 
 at least one sensor configured to measure a resisting force by said produce item as a function of an advancement distance; 
   at least one hardware processor; and   a non-transitory computer-readable storage medium having stored thereon program instructions, the program instructions executable by the at least one hardware processor to:
 a. operate said testing device to advance said probe to engage a surface of said produce item while measuring said resisting force, 
 b. detect a first exponentially-increasing resistance response phase of the resisting force occurring between 0.2-0.3 mm of the advancement distance, 
 c. detect a second linearly-increasing resistance response phase occurring between 0.3-3 mm of the advancement distance, 
 d. determine a transition point between the exponentially-increasing resistance response phase and the linearly-increasing resistance response phase by monitoring for a decrease in resistance force change between increments of the advancement distance, 
 e. discontinue said advancing and retrieve the probe when said transition point is detected, and 
 f. determine a transition resisting force and a transition distance at said transition point, wherein said transition point indicates a beginning of irreversible damage to the produce item. 
   
     
     
         2 . The system of  claim 1 , wherein said produce item is one of a fruit and a vegetable. 
     
     
         3 . The system of  claim 1 , wherein at least one of the transition resisting force and the transition distance is indicative of a ripeness parameter of said produce item. 
     
     
         4 . The system of  claim 1 , wherein said hardware processor is configured to iterate, steps a to f, with respect to a produce item of a specified variety, at two or more known ripeness stages of said produce item. 
     
     
         5 . The system of  claim 4 , wherein said transition resisting force and said transition distance are stored as firmness values indicative of a ripeness parameter of said specified variety at said two or more ripeness stages. 
     
     
         6 . The system of  claim 1 , wherein said advancing is performed in increments of a specified distance. 
     
     
         7 . The system of  claim 6 , wherein said specified distance is between 0.001 and 0.1 mm. 
     
     
         8 . A method for measuring firmness of a soft fruit, the method comprising:
 a. providing a testing device comprising:
 a probe configured to be advanced to engage a soft fruit positioned in relation to said testing device, wherein said soft fruit is characterized by having a soft texture that is easily mashed to pulp or follow viscous behavior when squashed, and 
 at least one sensor configured to measure a resisting force by said soft fruit as a function of an advancement distance; 
   b. operating said testing device to advance said probe to engage a surface of said soft fruit while measuring said resisting force;   c. detecting a first exponentially-increasing resistance response phase of the resisting force occurring between 0.2-0.3 mm of the advancement distance,   d. detecting a second linearly-increasing resistance response phase occurring between 0.3-3 mm of the advancement distance,   e. determining a transition point between the exponentially-increasing resistance response phase and the linearly-increasing resistance response phase by monitoring for a decrease in resistance force change between increments of the advancement distance,   f. discontinuing said advancing, and retrieve the probe when said transition point is detected; and   g. determining for the transition point, a transition resisting force and a transition distance at said transition point, wherein said transition point indicates a beginning of irreversible damage to the soft fruit.   
     
     
         9 . The method of  claim 8 , wherein said produce item is one of a fruit and a vegetable. 
     
     
         10 . The method of  claim 8 , wherein at least one of said transition resisting force and said transition distance is indicative of a ripeness parameter of said produce item. 
     
     
         11 . The method of  claim 8 , wherein said operating, discontinuing, and determining are iterated, with respect to a produce item of a specified variety, at two or more known ripeness stages of said produce item. 
     
     
         12 . The method of  claim 11 , wherein said transition resisting force and said transition distance are stored as firmness values indicative of a ripeness parameter of said specified variety at said to or more ripeness stages. 
     
     
         13 . The method of  claim 8 , wherein said advancing is performed in increments of a specified distance. 
     
     
         14 . The method of  claim 13 , wherein said specified distance is between 0.001 and 0.1 mm.